Wide and narrow satellite beams based ntn systems

Abstract

In one method, a wireless transmit receive unit (WTRU) receives a SSB and/or one or more SIBs through a wide beam from a non-terrestrial network (NTN) satellite. The decoded SIBs may provide a set of reference locations for narrow beams and several RACH configurations (or SSB-to-RACH occasion (RO) mappings) for narrow beams provided against reference timings and satellite location. The WTRU determines a suitable RACH resource based upon one or more of (i) WTRU location, (ii) reference locations for narrow beams, (iii) current time, (iii) reference timings for RACH configurations (or SSB-RO mappings) and (iv) satellite location. The WTRU transmits RACH over the determined RACH resource. In some embodiments the SIBs are received in a narrow beam based on SSB MIB information. In other embodiments, a narrow beam is selected based on CSI-RS measurements

1 . A method for use in a wireless transmit receive unit (WTRU), the method comprising:
 receiving, from a non-terrestrial network (NTN) satellite, a synchronization signal block (SSB) in a wide beam;   based on the received SSB, receiving from the NTN satellite, one or more system information blocks (SIBs) in the wide beam, to determine reference locations of a plurality of narrow beams within coverage of the wide beam, wherein the one or more SIBs indicate associated narrow beam reference timings and a plurality of random access channel (RACH) configurations corresponding to the plurality of narrow beams;   determining a select narrow beam from the plurality of narrow beams based on a current location of the WTRU and the reference locations of the plurality of narrow beams;   selecting a RACH configuration from the plurality of RACH configurations based on a location of the satellite, the associated narrow beam reference timings and a current time;   selecting a RACH resource based on the select narrow beam and the selected RACH configuration; and   sending, to the NTN satellite, a RACH transmission over the selected RACH resource.   
     
     
         2 . The method of  claim 1 , wherein the location of the WTRU is determined from a global network satellite system (GNSS) or a radio access technology (RAT) positioning method. 
     
     
         3 . The method of  claim 1 , wherein the plurality of RACH configurations comprise one or more SSB-to-RACH occasion (SSB-to-RO) mappings associated to one or more satellite locations. 
     
     
         4 . The method of  claim 1 , wherein the current time corresponds to one of a time of detection of the SSB, a time of detection of the one or more SIBs, or a time of expected RACH transmission. 
     
     
         5 . The method of  claim 1 , wherein the determining of the select narrow beam from the plurality of narrow beams based on the current location of the WTRU and the reference locations of the plurality of narrow beams comprises:
 selecting a narrow beam, as the select narrow beam, the narrow beam having a reference location closest to the current location of the WTRU.   
     
     
         6 . The method of  claim 1 , wherein the determining of the select narrow beam from the plurality of narrow beams based on the current location of the WTRU and the reference locations of the plurality of narrow beams comprises:
 selecting a narrow beam, as the select narrow beam, the narrow beam having a coverage area including the current location of the WTRU.   
     
     
         7 . The method of  claim 1 , wherein the reference locations of the plurality of narrow beams each correspond to geographic coordinates of a corresponding narrow beam central location. 
     
     
         8 . The method of  claim 1 , wherein the one or more SIBs comprise at least a SIB1 and a SIB19. 
     
     
         9 . The method of  claim 8 , wherein the SIB1 includes one or more of: a narrow beam configuration, a cell selection information, information of an availability and scheduling of one or more other SIBs, an indication of whether the one or more other SIBs are provided on a periodic broadcast or on a demand basis, serving cell configuration, or timers and constants for WTRU procedures. 
     
     
         10 . A wireless transmit receive unit (WTRU) comprising:
 a transceiver; and   a processor operatively coupled to the transceiver, wherein the transceiver and the processor are configured to:   receive, from a non-terrestrial network (NTN) satellite, a synchronization signal block (SSB) in a wide beam;   based on the received SSB, receive from the NTN satellite, one or more system information blocks (SIBs) in the wide beam, to determine reference locations of a plurality of narrow beams within coverage of the wide beam, wherein the one or more SIBs indicate associated narrow beam reference timings and a plurality of random access channel (RACH) configurations corresponding to the plurality of narrow beams;   determine a select narrow beam from the plurality of narrow beams based on a current location of the WTRU and the reference locations of narrow beams;   select a RACH configuration from the plurality of RACH configurations based on a location of the satellite, the associated narrow beam reference timings and a current time;   select a RACH resource based on the select narrow beam and the selected RACH configuration; and   send, to the NTN satellite, a RACH transmission over the selected RACH resource.   
     
     
         11 . The WTRU of  claim 10 , wherein the location of the WTRU is determined from a global network satellite system (GNSS) or a radio access technology (RAT) positioning method. 
     
     
         12 . The WTRU of  claim 10 , wherein the plurality of RACH configurations comprise one or more SSB-to-RACH occasion (SSB-to-RO) mappings associated to one or more satellite locations. 
     
     
         13 . The WTRU of  claim 10 , wherein the current time corresponds to one of a time of detection of the SSB, a time of detection of the one or more SIBs, or a time of expected RACH transmission. 
     
     
         14 . The WTRU of  claim 10 , wherein to determine the select narrow beam from the plurality of narrow beams based on the current location of the WTRU and the reference locations of narrow beams, the transceiver and the processor are further configured to:
 select a narrow beam, as the select narrow beam, from one of: the narrow beam having a reference location closest to the current location of the WTRU or the narrow beam having a coverage area including the current location of the WTRU.   
     
     
         15 . A method for use by a wireless transmit receive unit (WTRU), the method comprising:
 receiving, from a satellite in a non-terrestrial network (NTN), a synchronization signal block (SSB) in a wide beam;   based on the received SSB, receiving, in the wide beam from the satellite, one or more system information blocks (SIBs), wherein the one or more SIBs indicate reference signal (RS) configurations for a plurality of narrow beams within coverage of the wide beam and a plurality of random access channel (RACH) configurations for the plurality of narrow beams;   performing measurements on received RSs associated with the RS configurations to determine a select narrow beam;   determining a RACH resource and a transmission (Tx) filter for the select narrow beam; and   sending a RACH transmission using the Tx filter and the determined RACH resource.   
     
     
         16 . The method of  claim 15 , wherein the Tx filter corresponds to a WTRU Rx filter used to perform the measurements on the selected narrow beam. 
     
     
         17 . The method of  claim 15 , wherein determining the RACH resource for the select narrow beam is based on at least one the RSs associated with the select narrow beam. 
     
     
         18 .- 20 . (canceled)